gh-37810: build/pkgs/gambit: Remove
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Removing this broken experimental package, as proposed in 2020.
- Closes #30156
Also removing the module providing outdated "standalone instructions" to
use Gambit.
Keeping the various references to Gambit tagged with `# optional -
gambit`. This will be updated in the follow-up PR"
- #37809
The motivation for opening this PR to remove `gambit` now (2024) is that
it removes a remaining use of the function `sdh_setup_bdist_wheel` (the
old gambit Python package could not be installed using pip). This a step
for the modernization of the build frontend for Python packages in the
Sage distribution:
- #35618
### :memo: Checklist
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preview.
### :hourglass: Dependencies
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URL: https://github.com/sagemath/sage/pull/37810
Reported by: Matthias Köppe
Reviewer(s): John H. Palmieri
